SAN FRANCISCO (KPIX 5) — Keith Jackson, a man described by the FBI as the central figure in the corruption case involving State Sen. Leland Yee, remains in jail on Monday. Jackson, a former San Francisco School Board president, faces a list of charges involving guns, drugs, and a murder-for-hire plot.

Jackson is described as a well-known “political consultant.” KPIX 5 wanted to know what kind of political work he’s been doing, presumably for Yee. But the more we looked, the less we found.

“I know Keith Jackson, and I know him reasonably well,” former San Francisco Mayor Willie Brown told KPIX 5. “I’m shocked that he has been involved in the kind of things that are contained in this 137-page indictment.”

In those 137 pages (.pdf), Jackson is described as the crucial link between a Chinatown crime syndicate, and a California state senator.

To learn more about Jackson’s role in Bay Area politics, we started by looking at his consulting business.

“He’s not registered as a consulting firm in either the local or state databases where you would find a legitimate consulting firm,” said KPIX 5 political analyst Melissa Griffin.

“This company doesn’t appear to have any records, aside from him claiming to work for Jackson Consulting.”

According to campaign records and the FBI, the “Jackson Consulting” firm was based on the third floor of an apartment building in Pacific Heights.

But if Jackson was, in fact, working for State Sen. Yee, the job didn’t pay very well.

“One of the main indicators of a legitimate consulting business is that there are records showing that the campaign has paid you. In this case, there aren’t any,” Griffin said. “We looked at Leland Yee’s records from his secretary of state campaign and his mayor’s race in 2011, and could find no indication that Keith Jackson ever received any money from Leland Yee’s campaigns.”

To the contrary, Jackson gave money to Leland Yee’s campaign for California Secretary of State.

Records show $4,000 was given on June 23rd of last year, and two days later – another $4,000 from someone identifying themselves as a “partner” at Jackson’s firm.

On that very same day – the FBI’s criminal complaint shows a whole lot more than cash changed hands.

“If you look at the affidavit, you see there on page 64, where on June 25th, 2013, the agent paid Jackson $5,300 in cash in exchange for some guns. On that very same day, a $4,000 donation shows up to Yee’s secretary of state campaign on behalf of someone claiming to be a partner in this thing called Jackson consulting.”

“Now, did it actually come form that person? There’s not really a mechanism or a system to really investigate that. You pretty much take the candidate’s word for it,” said Daniel G. Newman, co-founder & president of Maplight.

It’s exactly the kind of thing political watchdogs have been screaming about for years: A system fueled by thousands upon thousands of donation checks, and virtually no one is double-checking the source of that money, or why it’s changing hands.

“What are they hoping to gain from a lawmaker – if anything? And that information the public is always in the dark about,” Newman said.

“There’s no one out there policing that,” Griffin said. “We just wouldn’t know, unless the FBI breaks down your door.”

It’s not just Willie Brown. KPIX 5 spoke with a number of people in the political world who have known and worked with Keith Jackson over the years. They all described him as a very likable guy and they all say they are stunned at the allegations.